I read this novel in French at least 20 years ago but it was much, much older.
Not very far after the beginning, a couple of scientist investigate some remarkable thing that takes place within living cells. They know it is dangerous but they see a great potential in harnessing this new phenomenon. Alas, by some lab accident, the wife (IIRC) is badly injured. Istead of giving up, they try to cure the illness by harnessing the very cause of it. In doing so, they create a frightening weapon.
I don't remember how their discovery becomes generally known.
From there on, the book is just a succession of horrors. Not only do people from one end of the Earth to the other keep sending destruction on each other, but even within one single area people kill each other. Indeed, they do not live in towns or cities. People build along roads. Those who live along north-south oriented roads ("méridiens") hate those who live along east-west oriented ones ("parallèles") and conversely.
At some point, so many people were said to have died in horrible ways, that it became a mystery to me who was still living to keep sending horrible death and how come they still had living targets to send it to.
I am not sure I managed to read it all. Maybe I made a fast-forward to the end. There, a group of survivors try to restart mankind almost from scratch. Sincerely, I think it was a bad idea. Better to let mankind rid Earth of itself.
What I remember best is what was on the "quatrième de couverture" of the paperback edition. That is, what is written on the back of the cover, where the editors ask someone to write a highly positive opinion so people who pick it up in the book store will buy it.
I was something like 'the greatest early french SF novel, the one that inspired many authors for decades, etc., etc.'
Well, was I disappointed !
